Rozhen Observation Calendar

Which nights are best for a target over the coming weeks. The astronomy mark (darkness × altitude × Moon) is computed for every night; the weather and the overall mark exist only where Open-Meteo has a forecast (the next four days) or ERA5 history (past nights) — the rest is honestly blank.

Best nights for Andromeda Galaxy: 07-14 (91), 07-13 (89), 07-12 (88), 07-11 (87), 07-10 (85) — by astronomy; check the weather when the night is within four days.

2027-06-15astronomy score per night — click a bar for that night2027-07-14

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2027-06-15 Tue	35	—	unknown	02:35–03:40 (good, 1.08 h)	89.6° 08:30	4.45	91%	145.4°
2027-06-16 Wed	32	—	unknown	02:30–03:40 (good, 1.17 h)	89.7° 08:25	4.44	96%	137.4°
2027-06-17 Thu	32	—	unknown	02:25–03:40 (good, 1.25 h)	89.7° 08:20	4.44	99%	128.1°
2027-06-18 Fri	32	—	unknown	02:25–03:40 (good, 1.25 h)	89.6° 08:15	4.43	100%	118.1°
2027-06-19 Sat	30	—	unknown	02:30–03:40 (good, 1.17 h)	89.5° 08:15	4.42	99%	107.8°
2027-06-20 Sun	27	—	unknown	02:30–03:40 (good, 1.17 h)	89.6° 08:10	4.42	97%	97.3°
2027-06-21 Mon	24	—	unknown	02:45–03:40 (good, 0.92 h)	89.7° 08:05	4.42	92%	86.9°
2027-06-22 Tue	23	—	unknown	03:25–03:40 (good, 0.25 h)	89.7° 08:00	4.42	87%	76.5°
2027-06-23 Wed	22	—	unknown	01:20–03:40 (marginal, 2.33 h)	89.6° 07:55	4.43	80%	66.3°
2027-06-24 Thu	23	—	unknown	01:15–03:40 (marginal, 2.42 h)	89.5° 07:55	4.43	72%	56.2°
2027-06-25 Fri	24	—	unknown	03:35–03:40 (good, 0.08 h)	89.7° 07:50	4.44	62%	46.7°
2027-06-26 Sat	28	—	unknown	02:10–03:40 (good, 1.5 h)	89.7° 07:45	4.45	53%	38.0°
2027-06-27 Sun	33	—	unknown	02:00–03:40 (good, 1.67 h)	89.7° 07:40	4.46	43%	31.3°
2027-06-28 Mon	41	—	unknown	01:50–03:40 (good, 1.83 h)	89.5° 07:35	4.48	32%	28.3°
2027-06-29 Tue	49	—	unknown	01:30–03:40 (good, 2.17 h)	89.6° 07:35	4.49	23%	30.7°
2027-06-30 Wed	56	—	unknown	01:25–03:45 (good, 2.33 h)	89.7° 07:30	4.51	14%	37.9°
2027-07-01 Thu	63	—	unknown	01:20–03:45 (good, 2.42 h)	89.7° 07:25	4.53	7%	48.1°
2027-07-02 Fri	65	—	unknown	01:20–03:45 (good, 2.42 h)	89.6° 07:20	4.55	2%	59.9°
2027-07-03 Sat	67	—	unknown	01:15–03:45 (good, 2.5 h)	89.5° 07:15	4.58	0%	72.8°
2027-07-04 Sun	70	—	unknown	01:10–03:45 (good, 2.58 h)	89.6° 07:15	4.6	1%	86.0°
2027-07-05 Mon	71	—	unknown	01:05–03:45 (good, 2.67 h)	89.7° 07:10	4.63	5%	99.4°
2027-07-06 Tue	75	—	unknown	01:00–03:50 (good, 2.83 h)	89.7° 07:05	4.66	11%	112.4°
2027-07-07 Wed	77	—	unknown	01:00–03:50 (good, 2.83 h)	89.6° 07:00	4.69	20%	124.7°
2027-07-08 Thu	79	—	unknown	00:55–03:50 (good, 2.92 h)	89.5° 07:00	4.72	30%	135.9°
2027-07-09 Fri	81	—	unknown	00:50–03:50 (good, 3.0 h)	89.7° 06:55	4.76	41%	145.0°
2027-07-10 Sat	85	—	unknown	00:45–03:55 (good, 3.17 h)	89.7° 06:50	4.79	52%	150.7°
2027-07-11 Sun	87	—	unknown	00:45–03:55 (good, 3.17 h)	89.7° 06:45	4.83	62%	151.4°
2027-07-12 Mon	88	—	unknown	00:45–03:55 (good, 3.17 h)	89.5° 06:40	4.87	72%	147.0°
2027-07-13 Tue	89	—	unknown	00:40–03:55 (good, 3.25 h)	89.6° 06:40	4.9	80%	139.5°
2027-07-14 Wed	91	—	unknown	00:40–04:00 (good, 3.33 h)	89.7° 06:35	4.95	88%	130.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2027-06-15&days=30"
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&days=30&format=csv" -o m31-calendar.csv

One row per night: score_astronomy always, score_weather / score only where a forecast or history exists (null otherwise, with weather_source saying which), best window, dark hours, Moon illumination and separation, transit. 7–60 nights. Errors: 400 with invalid_date or target_unresolved. Results are cached for six hours; calculation version 2026-10-10.1.